I always wondered this! The iconic Doctor's trainers were actually David Tennant's before he became The Doctor. It was his idea to wear them, and he was turned down at first due to the cold while filming. He pushed and eventually got his way.

Doctor Who Regenerations Names T-Shirt

Thirteen actors have portrayed thirteen iconic versions of the popular Doctor, and the Doctor Who Regenerations Names T-Shirt lists all thirteen, along with a clever way of showing how each becomes another. The cotton, navy blue